diff --git a/demo/README.md b/demo/README.md
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+# Demo application #
+
+This folder contains a demo application that uses ExoPlayer to play a number
+of test streams. It can be used as a starting point or reference project when
+developing other applications that make use of the ExoPlayer library.
diff --git a/demo_misc/README.md b/demo_misc/README.md
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+# Miscellaneous demos #
+
+This folder contains miscellaneous demo applications. For example applications
+that demonstrate use of optional extensions, or more advanced features.
+
+A general purpose ExoPlayer demo application can be found in the [demo](../demo)
+folder.
diff --git a/extensions/README.md b/extensions/README.md
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+# Extensions #
+
+This folder contains optional ExoPlayer extensions.